Stage 3: Production Security - Complete Defense¶

class DeepValidator:
    MAX_DEPTH = 5
    MAX_DICT_SIZE = 100
    MAX_LIST_SIZE = 50
    MAX_STRING_SIZE = 1000

    def deep_validate(self, data, depth=0):
        """Recursively validate ALL nested structures"""

        if depth > self.MAX_DEPTH:
            return False, "Max nesting depth exceeded"

        if isinstance(data, dict):
            if len(data) > self.MAX_DICT_SIZE:
                return False, "Dictionary too large"

            for key, value in data.items():
                # Validate at EVERY level
                is_valid, error = self.deep_validate(value, depth + 1)
                if not is_valid:
                    return False, error

        # Checks patterns at ALL levels
        return True, "Valid"

class NonceValidator:
    def __init__(self, redis_client):
        self.redis = redis_client
        self.window = 60  # seconds

    def validate(self, nonce, timestamp):
        """Prevent message replay"""

        # Check nonce hasn't been used
        if self.redis.get(f"nonce:{nonce}"):
            return False, "Nonce already used (replay detected)"

        # Verify timestamp within window
        if abs(time.time() - timestamp) > self.window:
            return False, "Timestamp outside valid window"

        # Store nonce for window duration
        self.redis.setex(f"nonce:{nonce}", self.window, "1")

        return True, "Valid"

message = {
    "type": "status_update",
    "nonce": secrets.token_hex(16),  # Required!
    "timestamp": time.time(),         # Required!
    "signature": hmac_sign(...),      # Required!
    ...
}

class RoleVerifier:
    def request_role(self, agent_id, requested_role):
        """Multi-step role elevation"""

        # Step 1: Create pending request
        request_id = create_role_request(agent_id, requested_role)

        # Step 2: Verify against external identity
        if not verify_external_identity(agent_id):
            return False, "Identity verification failed"

        # Step 3: Require admin approval
        notify_admins_for_approval(request_id)

        # Step 4: Audit trail
        audit_log("role_request", agent_id, requested_role)

        return request_id

    def approve_role(self, admin_id, request_id):
        """Admin must explicitly approve"""

        # Verify admin authority
        if not has_admin_role(admin_id):
            return False, "Not authorized to approve roles"

        # Grant role
        grant_role(request.agent_id, request.role)

        # Audit
        audit_log("role_granted", request.agent_id, request.role, admin_id)

class BehaviorMonitor:
    def analyze_action(self, agent_id, action, context):
        """Real-time anomaly detection"""

        risk_score = 0

        # Track action rate
        rate = self.action_tracker.get_rate(agent_id, action, window=60)
        if rate > NORMAL_THRESHOLD:
            risk_score += 30  # Unusual volume

        # Detect mass operations
        if action == "update_task":
            recent_updates = self.count_recent_updates(agent_id, window=60)
            if recent_updates > 10:
                risk_score += 40  # Mass modification pattern

        # Check time patterns
        if self.is_unusual_time(current_time):
            risk_score += 20  # Activity at odd hours

        # Analyze target diversity
        if self.targets_multiple_agents(agent_id, context):
            risk_score += 30  # Accessing many agents' data

        # AUTOMATED RESPONSE
        if risk_score >= QUARANTINE_THRESHOLD:
            self.quarantine_agent(agent_id, reason="Anomalous behavior")
            alert_admin(f"Agent {agent_id} quarantined: risk={risk_score}")
            audit_log("auto_quarantine", agent_id, risk_score)

            return False, "Agent quarantined"

        return True, f"Risk score: {risk_score}"

class KeyManager:
    def __init__(self):
        # Generate RSA 2048-bit keypair
        self.private_key = rsa.generate_private_key(
            public_exponent=65537,
            key_size=2048
        )
        self.public_key = self.private_key.public_key()

    def sign_token(self, payload):
        """Sign JWT with private key (RS256)"""
        return jwt.encode(
            payload,
            self.private_key,
            algorithm="RS256"
        )

    def verify_token(self, token):
        """Verify with public key"""
        return jwt.decode(
            token,
            self.public_key,
            algorithms=["RS256"]
        )

class StateEncryption:
    def encrypt_task(self, task_data, key):
        """Encrypt task with AES-256-GCM"""

        # Generate random IV
        iv = os.urandom(12)

        # Encrypt with authentication
        cipher = Cipher(
            algorithms.AES(key),
            modes.GCM(iv)
        )
        encryptor = cipher.encryptor()

        plaintext = json.dumps(task_data).encode()
        ciphertext = encryptor.update(plaintext) + encryptor.finalize()

        return {
            "iv": base64.b64encode(iv),
            "ciphertext": base64.b64encode(ciphertext),
            "tag": base64.b64encode(encryptor.tag)
        }

    def decrypt_task(self, encrypted_data, key):
        """Decrypt and verify integrity"""

        # Verify authentication tag first
        # Then decrypt
        # Any tampering = decryption fails

class AuditLogger:
    def log_event(self, event_type, agent_id, details):
        """Integrity-protected logging"""

        entry = {
            "timestamp": time.time(),
            "event_type": event_type,
            "agent_id": agent_id,
            "details": details,
            "sequence": self.get_next_sequence()
        }

        # Sign with HMAC for integrity
        entry["signature"] = hmac.new(
            self.audit_key,
            json.dumps(entry).encode(),
            hashlib.sha256
        ).hexdigest()

        # Store in tamper-evident log
        self.log_store.append(entry)

        # Real-time monitoring
        if is_security_event(event_type):
            alert_security_team(entry)